.xls

Excel 97-2003

Handled by macOS itself

Format facts

MIME type: application/vnd.ms-excel
Apple UTI: com.microsoft.excel.xls
Stock Quick Look: no stock preview
Planned approach (census): native-sufficient
Icon hint: renders
Prevalence: common

Renderer note (from the census)

macOS handles this natively

Gotchas: legacy OLE2 binary format